With the deployment of 3G wireless communication networks, the demand for data service has increased dramatically. To maximize spectrum efficiency, intra-frequency networking has been used in wireless networks such as LTE. Intra-frequency networking means that each neighboring cell uses the same carrier. Different User equipment (UE) in the neighboring cells, especially those at the cell edge, may receive two or more signals of the same frequency at the same time. If these co-frequency signals from various cells are strong, UEs will suffer severe interference and the quality of their communication will be deteriorated. Inter-Cell Interference Coordination (ICIC) was introduced in 3rd Generation Partnership Project (3GPP) Release 8 to solve inter-cell intra-frequency interference.
FIG. 1 shows a schematic view of a downlink frequency band allocation scheme in a traditional ICIC solution. In the example as shown in FIG. 1, for the closest three intra-freq neighbor cells in geography, the whole bandwidth is divided into three subbands which are indicated by different patterns in FIG. 1. Each subband consists of resource block groups (RBGs) that are consecutive in frequency. The allocation of subbands is statically and permanently configured in Operations & Maintenance (O&M). Different subbands are allocated to the edge of different cells, and the whole bandwidth is reused in the centre of each cell. For the UE(s) located in cell center, the evolved NodeB (eNB) will first allocate the RBGs in the subband which belongs to other cells, but for the cell-edge UE(s), the eNB will allocate the RBGs in the corresponding subband. By allocating different subbands to the edge of different cells, UEs at the edge of one cell will not receive strong co-frequency signals from neighbouring cells.
However, in such an ICIC solution, in case that some UEs encounter frequency-selective fading and the subband allocated to their serving cell unfortunately locates on the bottom of the fading, the signal deterioration will become unavoidable.